Privacy Policy

This Privacy Policy explains how Noctium ("the app"), developed by Obelisk Agency, handles your information. We are committed to protecting your privacy and ensuring transparency about our data practices.

1. Data Collection

The app collects and stores the following data locally on your device:

• Your ebook and audiobook library (imported files, metadata, cover images)
• For books you read in place from a folder you choose, a reference to each file's location on your device. The app reads these files directly from your folder and never copies them off the device or transmits them.
• Reading progress, bookmarks, highlights, and annotations
• Reading statistics (time spent reading, pages read, streaks)
• App preferences (theme, font settings, playback speed, display options)
• Server connection details (URLs and credentials for self-hosted servers such as Calibre-Web, Kavita, Komga, Stump, BookLore, Audiobookshelf, and Storyteller, and for WebDAV shares such as Nextcloud, ownCloud, or a NAS)

We do not create user accounts. No personal data is collected by Obelisk Agency unless you explicitly choose to use optional features described below.

2. Data Storage

All core app data is stored exclusively on your device using local databases and encrypted preferences. We do not operate servers that store your personal data.

3. Optional Google Drive Backup

If you choose to sign in with your Google account, the app can back up your reading progress and preferences to your Google Drive. This backup is stored in a private, app-specific folder that is invisible in your Google Drive. Uninstalling Noctium from your phone does not delete it. To delete it, in Google Drive on the web, open Settings → Manage apps, find Noctium, and choose Options → Delete hidden app data.

When you sign in, we access:

• Your Google account email address and display name (shown in the app to confirm which account is connected)
• Google Drive App Data scope (to read and write backup files only)

We do not access any other files on your Google Drive.

4. Third-Party Services

The app integrates the following third-party services:

• Google AdMob: Displays advertisements in the free version of the app (not shown on reading or audiobook playback screens). AdMob receives the Android Advertising ID (which you can reset or opt out of at the operating system level), coarse device information, and IP address, according to Google's Privacy Policy. In the European Economic Area, United Kingdom, and Switzerland, Noctium shows a Google-provided consent form (UMP) on first launch so you can decide whether personalized ads may use your data; you can change your choice at any time from Settings → Privacy & Data → Ad privacy options. You may remove all ads by purchasing the premium upgrade.
• Google Play Billing: Processes the in-app purchase for ad removal. We do not have access to your payment information.
• Firebase Crashlytics & Analytics: Collects anonymous crash reports and aggregate app-usage events (screen views, feature interactions) to help us fix bugs and improve stability. Data includes a Firebase Installation ID, device model, OS version, and crash stack traces; it does not include your library, bookmarks, highlights, or server credentials. You can disable crash reporting and analytics at any time from Settings → Privacy & Data → Share anonymous analytics & crash reports. Collection is always off in debug builds.
• Google Cast (optional): When you cast an audiobook, Google Play services finds Cast devices on your network and your Cast device loads Google's media receiver to play it, under Google's Privacy Policy. See Network Requests below.
• Readwise (optional): Receives your highlights, their notes, and each book's title and author, only if you connect it with your own access token. See Network Requests below and Readwise's Privacy Policy.
• Hardcover (optional): Receives the title, author, ISBN and reading position of the books you read, whether you finished them, and your new highlights; and is asked, for those books, for their status and page on your Hardcover shelf. Only if you sign in with Hardcover. See Network Requests below and Hardcover's policies.
• Google Sign-In: Used only for Google Drive backup functionality. We only access your email address for display purposes and your Drive storage (App Data scope) for backup files.

5. Network Requests

The app makes network requests in the following scenarios:

• Project Gutenberg (OPDS): Browsing and downloading free public domain ebooks. Search queries and download requests are sent to gutenberg.org.
• LibriVox and the Internet Archive: Browsing, streaming and downloading free public domain audiobooks. Search queries are sent to librivox.org. The recordings and their cover images are not hosted by LibriVox itself: they are served from the Internet Archive (archive.org), which therefore receives your IP address and the identifier of the audiobook you play or download.
• Book metadata and cover images (optional, on by default): When a book is added without a cover or description, the app searches for one by title and author. Queries are sent to the iTunes Search API (Apple), Google Books, Open Library, and Wikidata (wikidata.org, used only to find which series a book belongs to). For comics and manga, the title is also sent to AniList (graphql.anilist.co), which covers those far better than the general book catalogues; cover images found there are downloaded from anilist.co. Only the book's title and author are sent, never your library, your reading position, or anything identifying you beyond the network request itself. You can switch all of this off under Settings → Library → "Look up covers and details online", after which a book keeps only what its own file contains. PDFs and comic archives take their cover from the book's own first page, so they do not need this lookup for a cover. When a cover or description comes from one of these services, the book's page names the source and links to the book's page there; opening that link is up to you.
• Dictionary download (only when you ask): Offline dictionaries are not included in the app. When you install one from Settings, it is downloaded from Google Play. No personal data is sent: Google Play receives the request as part of delivering the app, and Obelisk Agency receives nothing.
• Dictionary and word lookup: Looking up a word or phrase while reading. An installed offline dictionary is used first, and works with no network at all; otherwise the selected text is sent to dictionaryapi.dev for definitions, and, if that service does not answer or has no entry, to Wiktionary (en.wiktionary.org, run by the Wikimedia Foundation); or to Wikipedia (wikipedia.org) for an encyclopedic explanation. Definitions shown from these sources are credited to Wiktionary, whose text they are. The lookup sheet also offers a “Search Google” button: tapping it hands the word to your browser as an ordinary Google search, so Google receives it the same way it would if you typed it yourself. Noctium makes no request to Google on your behalf, and nothing is sent unless you tap that button.
• Translation (only when you use Translate): Selected text is translated on your phone by Google ML Kit; the text itself is not sent anywhere. The first time you translate into a language, its language model is downloaded from Google. ML Kit also sends Google metrics about how the translation feature performs and is used, which Google uses to maintain and improve it and to detect misuse, under the ML Kit terms and Google's Privacy Policy. Translations are marked “powered by Google Translate”.
• KOReader progress sync (optional, off by default): If you enable KOReader sync, the app connects to a kosync-compatible sync server (a default public server, or one you self-host) to share your reading position across devices and apps. It sends your sync username, an authentication key derived from your password (never the password itself), a fingerprint of the book file, your reading progress, and your device model. Your credentials are stored in encrypted local storage.
• Wear OS watch (optional): If you install Noctium on a Wear OS watch, the watch and your phone exchange page-turn commands and whether a book is open, through Google Play services' connection between your own paired devices. No book content, reading position or personal data is sent.
• Casting audiobooks (optional, only while you cast): When you choose a Cast device from the player, the app serves the audiobook's audio and cover to that device over your local Wi-Fi, along with the book's title, author and chapter names so they can be shown on it. The audio is served from your phone to your Cast device only, at addresses that stop working when the cast ends; it is not uploaded to us or to any server.
• Readwise highlight export (optional, off until you connect): If you paste a Readwise access token (Settings → Readwise), the app sends your highlights to Readwise (readwise.io): the highlighted text, any note you added, the book's title and author, where the highlight sits in the book, and when you made it. Nothing else from your library is sent. The token is stored in encrypted local storage and is never included in backups. Deleting a highlight in Noctium does not delete it from Readwise; manage those on readwise.io. Disconnecting removes the token from the device.
• Hardcover reading sync (optional, off until you connect): If you sign in with Hardcover (Settings → Hardcover), the app talks to Hardcover (api.hardcover.app). To find each book you read there it sends the book's ISBN, or its title and author. It then sets the book to “Currently reading” with the page you have reached (worked out from your progress and the length of Hardcover's edition), and to “Read” when you finish; a book already on your Hardcover shelf keeps the privacy you gave it there. New highlights are added to your Hardcover reading journal as private quotes (the highlighted text only; notes are not sent). For the books it has matched, the app also reads back from your Hardcover shelf their status, when that last changed, and the page of the read in progress, so that a page you reached on another device opens here and a book you finished elsewhere shows as finished here; what it reads stays on your device. Audiobooks are not sent or read back. You can turn progress and highlights off separately. The sign-in's tokens are stored in encrypted local storage and are never included in backups. Nothing on Hardcover is deleted by the app; manage your shelf and journal on hardcover.app. Disconnecting removes the token and the app's record of which books it matched from the device, and withdraws a sign-in on Hardcover's side.
• Self-hosted servers and WebDAV shares: If you configure connections to Calibre-Web, Kavita, Komga, Stump, BookLore, Audiobookshelf, or Storyteller servers, or to a WebDAV share (for example Nextcloud, ownCloud, or a NAS), the app communicates directly with those servers using the credentials you provide. Noctium uses HTTPS when your server supports it and also permits plain HTTP so you can connect to servers on your own local network that do not have a TLS certificate. Your credentials are stored in encrypted local storage regardless of transport and are never sent to Obelisk Agency.

6. Data Sharing

We do not sell, rent, or share your personal data with third parties. Data leaves your device only when you explicitly use features that require network communication (as described above) or through the third-party SDKs listed in Section 4.

7. Permissions

• Internet: Required for downloading books, streaming audiobooks, ads, crash reporting, and server connections.
• Storage / Media Audio (Android 12 and below): Required to import audiobook files from your device.
• Notifications: Used for audiobook playback controls and download progress.
• Foreground Service (Media Playback): Required to continue audiobook playback when the app is in the background.
• Wake Lock: Prevents the device from sleeping during audiobook playback.

8. Security

All communication with Google, Firebase, AdMob, and public third-party APIs uses HTTPS. Self-hosted server connections use HTTPS whenever the server supports it and plain HTTP only when you point Noctium at a non-TLS endpoint on your own network. Server credentials are kept in encrypted local storage regardless of transport. Google Drive backup data is transmitted over Google's encrypted channels. When you connect to a server over plain HTTP, Noctium tells you so on the screen where you enter its address, before you type a password. Noctium also excludes its own files from Android's system backup and device-transfer features, so your books, covers and saved credentials are never copied to the cloud by the operating system — the optional Google Drive backup described above is the only cloud copy Noctium makes, and it never contains book files or credentials.

9. Children's Privacy

Noctium is not directed at children under the age of 13. We do not knowingly collect personal information from children. If you believe a child has provided us with personal data, please contact us and we will delete it.

10. Your Rights

For users in the European Economic Area (EEA), you have additional rights under the GDPR, including the right to access, rectify, and erase your data. Since all data is stored locally on your device, you exercise these rights directly through the app.

For users in California, you have rights under the CCPA/CPRA. We do not sell personal information. You may request deletion of your data by uninstalling the app.

11. Changes to This Policy

We may update this Privacy Policy from time to time. Changes will be reflected by updating the "Last updated" date. Continued use of the app after changes constitutes acceptance of the updated policy.